Add lots of debugging machinery for flaky datetime creation

pkg/intl/lib/src/date_format_helpers.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 
 part of intl;
 
 /**
  * A class for holding onto the data for a date so that it can be built
  * up incrementally.
@@ skipping 21 matching lines @@
   void setSecond(x) { second = x; }
   void setFractionalSecond(x) { fractionalSecond = x; }
 
   /**
    * Return a date built using our values. If no date portion is set,
    * use the "Epoch" of January 1, 1970.
    */
   DateTime asDate() {
     // TODO(alanknight): Validate the date, especially for things which
     // can crash the VM, e.g. large month values.
+    if (debugLogDateCreation) {
+      debugDateCreationLog
+        ..write("  Creating Date from\n")
+        ..write("    UTC: $utc\n")
+        ..write("    year: $year\n")
+        ..write("    month: $month\n")
+        ..write("    day: $day\n")
+        ..write("    pm: $pm\n")
+        ..write("    hour: $hour\n")
+        ..write("    minute: $minute\n")
+        ..write("    second: $second\n")
+        ..write("    fractionalSecond: $fractionalSecond\n");
+    }
+    var result;
     if (utc) {
-      return new DateTime.utc(
+      result = new DateTime.utc(
           year,
           month,
           day,
           pm ? hour + 12 : hour,
           minute,
           second,
           fractionalSecond);
     } else {
-      return new DateTime(
+      result = new DateTime(
           year,
           month,
           day,
           pm ? hour + 12 : hour,
           minute,
           second,
           fractionalSecond);
     }
+    if (debugLogDateCreation) {
+      debugDateCreationLog
+        ..write("Created $result");
+    }
+    return result;
   }
 }
 
 /**
  * A simple and not particularly general stream class to make parsing
  * dates from strings simpler. It is general enough to operate on either
  * lists or strings.
  */
 class _Stream {
   var contents;
@@ skipping 63 matching lines @@
    * can see and then return the corresponding integer. Advance the stream.
    */
   var digitMatcher = new RegExp(r'\d+');
   int nextInteger() {
     var string = digitMatcher.stringMatch(rest());
     if (string == null || string.isEmpty) return null;
     read(string.length);
     return int.parse(string);
   }
 }